DAX formula not working

[ChubbChubb]

I'm triyng to add a subtitle to acard to display national data.

The formula that works looks like this 

KPI Attendance Target = format(Product('Academy Info'[Attendance Target]),"KPI #%"&""). It is turning a percentage column into a text column to then use as a subtitle on the card.

I have tried to use the same formula for a different set of data 

Nat Ebacc Entry = format(Product('National Headline Data'[Nat Ebacc Entry]),"Nat #.#%"&"")

and instead I get this

I find that If I change the "Nat" to "KPI" it works fine, but if I use the letters N or S they get changed to 41&17 and code doesn't work.

I have checked that the two source columns are set up exactly the same way, just can't fathom it out?

TIA 

[olgad · Accepted solution]

Hi, dont place NAT  into format function

 "Nat " & format(Product('Academy Info'[Attendance Target]," #%"&"")

[ChubbChubb]

Thank you for that, I had copied the forumla from somewhere else so wasn't sure on it. Do you know why it was replacing the letters for number?